Humans have been interested in celestial observation and the science of astronomy since at least the time of Copernicus. For amateur astronomers, it can be difficult to identify particular celestial objects, to locate particular objects by name or to locate deep space objects (DSOs).
The prior art has evolved a number of devices which may be used by amateur astronomers to identify celestial objects viewed through their respective viewing channels. Such devices are disclosed, for example, in:    U.S. Pat. No. 5,311,203;    U.S. Pat. No. 6,366,212;    U.S. Pat. No. 6,570,506;    U.S. Pat. No. 6,844,822;    U.S. Pat. No. 7,068,180;    US patent application No. 2008/0168492; and    US patent application No. 2008/0163504.
The prior art has also evolved so-called planetarium software for use on personal computers. Such planetarium software receives user input, such as longitude, latitude, local time, compass heading angle (azimuth) and elevation angle. In response to this input, the planetarium software displays, on the computer monitor, representations of a corresponding area of the night sky including pre-stored representations of celestial objects and their names. Examples of such planetarium software include:
SkyMap™ from SkyMap Software of Chesire, England;
Starry Night™ from Imaginova, Corp. Santa Crux, Calif.; and
TheSky™ from Software Bisque, Inc. of Golden, Colo.
These prior art devices and software can be difficult to use with ease and/or accuracy. There remains a general desire for personal planetarium devices which can be used with ease and accuracy.